Method of continuously dyeing and stretching undrawn yarn



March 25, 1969' BUCK ET 3,434,189

METHOD OF CONTINUOUSLY DYEING AND STRETCHING UNDRAWN YARN Filed Aug. 2, 1966 DRY INVENTORS THOMAS M. BUCK FRED B. SATTERWHITE BY 77% Ma- ATTORNEYS United States Patent METHOD OF CONTlNUOUSLY DYEING AND STRETCHING UNDRAWN YARN Thomas M. Buck, New York, N.Y., and Fred B. Satterwhite, Williamsburg, Va., assignors, by mesne assignments, to The Klinger Manufacturing Company, Limited, London, England, a corporation of Great Britain Filed Aug. 2, 1966, Ser. No. 569,717

Int. Cl. D02j 1/ 22; D06p 3/00 US. Cl. 28---75 10 Claims ABSTRACT OF THE DISCLOSURE The invention relates to treating yarn and more particularly continuous filament theremopalstic yarn or yarn having a thermoplastic component.

It is known to produce yarn for textile purposes by extruding yarn as continuous filaments, drawing the yarn to orientate the filament molecules and improve the tensile strength of filaments, dyeing and then texturising the yarn, for example, by stutter box or false twist crimping.

In one yarn dyeing process, yarn is treated with dye solutions, excess dye solvent is then removed from the yarn and then the dye is set and bonded to the yarn. Setting is carried out by raising the temperature of the yarn and dye applied thereto and maintaining them at a raised temperature for a predetermined time interval. The dyed yarn is then washed and dried to complete the process.

The speed and elficiency of the production of dyed yarn is limited at least in part by the ability and speed of the yarn to take up dye and the strength of dye solution that is used.

It is an object of the present invention to provide an improved method and apparatus for treating yarn in the production of dyed yarn.

According to one aspect of the invention a method for treating yarn comprises applying dye to undrawn yarn, and then drawing the dyed yarn.

The term undrawn yarn used throughout the specification refers to yarn normally produced by presently employed yarn extruders. In some instances so-called undrawn yarn may be in fact slightly drawn after extrusion before being supplied to drawing and texturing apparatus. Even though such yarns are slightly drawn to provide a small degree of orientation of yarn filament molecules, the yarn is nevertheless generally referred to in the art as undrawn yarn. Before such undrawn yarn can be supplied to texturising apparatus, for example, and later made up into finished garments it is necessary to draw the yarn and extend its length by at least, say, two times. Thus, in the specification we intend the meaning of the term undrawn yarn to include yarn with a small degree of orientation of its molecules.

We believe that when yarn has been drawn it exhibits a core-surface aflect" which causes the outer surface of the yarn to resist the bonding of dye thereto and the impregnation of dye therethrough. Whereas we have found 3,434,189 Patented Mar. 25, 1969 that undrawn yarn due, we believe, to its comparatively open physical structure more readily takes-up dye so that undrawn yarn can be dyed more quickly or dyed using a less concentrated dye solution than drawn yarn and at the same time achieve the same dyeing affect.

We have also found that if undrawn yarn is dyed and then drawn, the dye is more effectively bonded to the yarn. We believe this is due to deeper penetration of dye in the yarn and the core-surface effect produced by drawing tends to retain the dye in the yarn. In this instance the core-surface affect tends to prevent dye passing through the yarn surface from within the yarn, for example, during washing of articles into which the yarn is knitted.

The invention is more particularly, but not exclusively, applicable to space dyeing of yarn.

In one known space dyeing process drawn yarn is first immersed in a dye solution to provide a background yarn color and then a different colored dye is impressed on the yarn at intervals along its length to provide a pattern of the different color on the background color. Excess dye solvent is then removed from the yarn, the dye is set and the dyed yarn is washed and dried.

The speed of the yarn in such a space dyeing process is determined by the speed at which the drawn yarn can take-up dye and the concentration of the dyes' used.

It is another object of the invention to provide an improved space dyeing rocess.

According to another aspect of the invention a method of treating yarn comprises applying dye in a space dyeing process to undrawn yarn, removing excess dye solvent, setting the dye, washing and drying the yarn, and then drawing the yarn to produce dyed drawn yarn.

According to another aspect of the invention a method of treating yarn comprises applying dye in a space dyeing process to undrawn yarn, removing excess dye solvent, setting the dye, drawing the yarn to produce dyed drawn yarn, and then washing and drying the dyed drawn yarn.

In one embodiment of the invention a method of treating yarn on the run comprises passing the yarn through a dye bath to provide the yarn with a general background color, impressing at least one other dye at intervals onto the yarn along its length to produce a pattern on the yarn, removing excess dye solvent, setting the dye, washing the yarn, drying the yarn, and then drawing the yarn to produce dyed drawn yarn.

According to another aspect of the invention apparatus for space dyeing undrawn yarn and then drawing the yarn comprises means for applying dye to undrawn yarn, means for removing excess dye solvent, means for setting the dye, means for washing the yarn, means for drying the yarn, and means for drawing the yarn.

In one embodiment of the invention apparatus for treating yarn in a continuous space dyeing process comprises at least one dye bath containing a dye solution, means for feeding undrawn yarn and immersing that yarn in the dye solution, one or more dye impressing means for impressing further dye on to the yarn at intervals along its length, a first heated chamber for removing excess dye solvent from the yarn after the dyes have been applied, a second heated chamber for setting the dyes on the yarn, a third heated chamber for drying the yarn after it has been washed, and drawing rollers for drawing the dyed undrawn yarn to produce dyed drawn yarn.

Hitherto space dyeing has not been applied to undrawn yarn before drawing and we have found many advantages in dyeing yarn in an undrawn state. For the same concentration of dye, compared to drawn yarn, more undrawn yarn can be dyed to the same extent. The speed at which the yarn can be treated is also increased compared to that in dyeing drawn yarn so that the through speed of yarn 3 can be increased. Alternatively, the through speed may be kept the same as before and a weaker concentration of dye may be used for the same dyeing affect, so that in the step of removing excess dye solvent before setting the dye, as the concentration of dye used is weaker, less dye is wasted.

By drawing the yarn after it has been dyed the original dye pattern on the yarn is extended to produce an aesthetically pleasing new pattern due to extending the original pattern.

It sometimes happens in space dyeing that the original pattern impressed on the yarn is blotchy and the dye is unevenly distributed to give sharp changes of tone or shade in the yarn. We have found that blotchiness is less likely to occur in dyeing undrawn yarn due to the more porous nature of undrawn yarn. The dye solution tends to penetrate more evenly and disperse or spread in the undrawn yarn. In any event, as mentioned above, subsequent drawing tends to produce an aesthetic pleasing affect and tends to remove the blotchiness and the sharp changes of tone or shade. If drawn yarn is dyed by space dyeing the blotchiness and sharp changes of tone or shade tend to remain on the finished dyed yarn.

A process and apparatus for space dyeing undrawn yarn according to the invention will now be described by way of example with reference to the accompanying drawing, which shows schematically one space dyeing arrangement.

Referring to the drawing, a plurality of undrawn yarns (up to, say 400) are fed in parallel into a dye bath 11 (at a temperature of approximately 70 F.-100 P.) where they are immersed in, say, a green dye solution by a roller 12. The yarns then travel to another dye bath where they pass between intermittently impressing rollers 13 and 14. The roller 14 dips at its lower edge into a dye bath 15 (at a temperature of approximately 70- 100 F.) filled with, say, blue dye solution, so that on rotation its upper surface carries a ifilm of blue dye solution. The roller 13 has four protrusions spaced around its periphery so that as this roller rotates the protrusions engage the yarns and urge them down onto the roller 14 so that the yarns take up blue dye intermittently at intervals along their length. In this way, a blue pattern is pro duced on a green background as the yarns pass between the rollers 13 and 14.

Thereafter, the yarns are dried in a drying chamber 16 by an infra-red heater (arranged to apply a temperature of approximately 200 F. to the yarns) to drive excess dye solvent from the yarn. The yarns are then passed through a setting chamber 17 (at a temperature of approximately 200250 F.) in which they are heated by an infra-red heater or dry steam to set and bond the dye to the yarns.

After setting, the yarns are washed in a water bath 18 which contains a washing solution of suitable detergent or soap (at a temperature of approximately 210 F.). The yarns are then dried in a drier 19, passed over a guide pulley 20 and fed to drawing rollers 21 Where the yarns are drawn in a known manner. The yarns are then wound onto a cheese 22.

It has been mentioned above that one advantage of space dyeing undrawn yarn is that undrawn yarn tends to take up dye solution more quickly than drawn yarn. We have found that the speed of yarn through the dyeing process may be increased 2 to 4 times compared to prior processes of dyeing drawn yarn where speeds of 1 to 15 meters per minute have been used. In the process described, the yarns are drawn after dyeing to 2 to 6 times their undrawn length so that the overall speed at which drawn dyed yarn is produced by this process is 4 to 24 times greater than before. At these increased speeds it is possible for the dyed yarn so produced to be supplied directly into modern high speed texturizing machines. Hitherto, the speed at which dyed yarn could be produced by space dyeing drawn yarn was normally too slow for feeding the dyed yarn directly and efficiently into a modcm high speed texturizing machine.

It will be appreciated that the process described may include steps for treating the yarns with conventional additives to improve the finished dyed yarn, such additives include color fixers, lubricants, optical brighteners, antioxidant agents, delusterants, anti-soiling agents, anti-static agents, and dye sites for receiving additional dyes. We have found that such additives are conveniently applied to the yarn in the described process before drawing and due to the open structure of the yarn the advantages hitherto described with respect to dye take-up and peneration are achieved. The additives are chosen according to the requirements dictated by the use for which the dyed drawn yarn is required.

It will also be appreciated that other dye patterns may be achieved, instead of the described blue pattern on a green background, by passing the undrawn yarn through a plurality of dye rollers. In such a process, the yarns may be passed through a dye bath before passing between the plurality of dye rollers. The patterns may be arranged to be applied by other techniques known in the space dyeing art such as, for example, by a printing press arranged to engage the yarns periodically and print a dye solution onto the surface of the yarns and thereby create a pattern on the yarn. Further, the patterns may be varied along the lengths of the yarns by printing at unequal intervals in time or by arranging the protrusions on the roller 13 to be non-symmetrically positioned around the periphery of that roller.

As explained above the speed at which the dyeing of yarns can be achieved is increased by the present invention so that the invention can provide dyed yarn at speeds comparable with yarn input speeds of modern high speed texturizing apparatus. At higher dyeing speeds it is practical to dye undrawn yarn as it is produced by an extruder. In such a process, extruded yarn is supplied directly into a space dyeing process according to the invention. It is envisaged that in combination with high speed yarn extruders the invention could provide a new continuous process comprising extruding yarn, dyeing the yarn, drawing the yarn and then texturizing the dyed drawn yarn.

What is claimed is:

1. A method of continuously treating yarn comprising dyeing 0n the run yarn which is completely undrawn along its entire length and then while the yarn is still on the run drawing the yarn.

2. A method of continuously treating yarn comprising applying dye to undrawn yarn on the run in a space dyeing process, said yarn being entirely undrawn along its entire length, removing excess dye solvent, setting the dye, washing the yarn, drying the yarn, and then while the yarn is still on the run drawing the yarn to produce dyed drawn yarn.

3. A method of treating yarn according to claim 2, comprising passing the undrawn yarn on the run through at least one dye bath to dye the yarn along its length with a general background color.

4. A method of treating yarn according to claim 2, comprising passing the undrawn yarn on the run through at least one set of intermittently impressing dye rollers to dye the yarn at intervals along its length.

5. A method according to claim 2, including applying additives to the yarn, to improve the finished dyed yarn, prior to drawing the yarn.

6. A method of continuously treating yarn comprising applying dye to yarn on the run in a space dyeing process, said yarn being entirely undrawn along its entire length, removing excess dye solvent, setting the dye, drawing the yarn while the yarn is still on the run to produce dyed drawn yarn, washing the dyed drawn yarn, and then drying the dyed drawn yarn.

7. A method according to claim 6, including applying additives to the yarn, to improve the finished dyed yarn, prior to drawing the yarn.

8. A method of continuously treating yarn comprising passing on the run yarn which is completely undrawn along its entire length through a dye bath to provide yarn with a general background color, impressing another dye at intervals onto the yarn along its length to produce a pattern on the yarn, removing excess dye solvent, setting the dye, washing the yarn, drying the yarn, and then while the yarn is still on the run drawing the yarn to produce dyed drawn yarn.

9. A method for continuously producing dyed drawn yarn comprising extruding the yarn without collecting the resultant undrawn yarn, applying dye to the undrawn yarn n the run in a space dyeing process, removing excess dye solvent, setting the dye, Washing the yarn, drying the yarn, and then while the yarn is still on the run drawing the yarn.

10. A method of continuously treating yarn on the run comprising applying dye to undrawn yarn, removing excess dye solvent, setting the dye, Washing the yarn, drying the yarn, drawing the yarn and then while the yarn is still on the run feeding the dyed drawn yarn on the run into a texturizing apparatus.

References Cited UNITED STATES PATENTS OTHER REFERENCES Rayon Textile Monthly; July 1944; The Processing of Nylon Textile Yarns and Fabrics; pp. 57 and 58.

LOUIS K. RIMRODT, Primary Examiner.

U.S. Cl. X.R. 8-14 

